Negative Photoinduced Birefringence in PQ/PMMA Photopolymer Materials

Phenanthraquinone-doped poly (methyl methacrylate) (PQ/PMMA) photopolymers have been considered a promising holographic recording medium for polarization holography due to their neglectable shrinkage, controllable thickness, and photoinduced anisotropy. Past studies have demonstrated that the polarization properties of PQ/PMMA materials are caused by the anisotropy of the photosensitizer PQ molecules. In addition, when measuring the photobirefringence value of the PQ/PMMA material, we can obtain a curve of photobirefringence values that is positively correlated with time. We prepared a new photopolymer material based on PQ/PMMA material. Specifically, we introduced the photoinitiator Triethanolamine (TEA) on the basis of PQ/PMMA material. Then we use the experimental optical path to record two beams of the orthogonal polarization interference light. By measuring the polarization state of diffracted light and the photoinduced birefringence curve of the material, we found the negative photoinduced birefringence phenomenon in PQ/PMMA material for the first time.